Tabletting machines in the form of rotary presses have a die-disk driven about a vertical axis which receives die-plates arranged on a circle in appropriate die-bores. Couples of compaction rams, which are actuated by control cams and pressure rollers if rotating along with the rotor, rotate in synchronism with the disk. Before being introduced into the die-plates, the upper rams are filled with an appropriately proportioned powder by means of a suitable loading device. Subsequently, the material is compressed to obtain a desired thickness (web height) by moving the compaction rams towards each other.
The control of the tabletting machine and its supervision, i.e. the control of its number of revolutions, the regulation of its filling level, the compaction force of the rams, the regulation of web height, and sampling, etc., is accomplished via a process control computer.
Different tablet shapes can be produced by making changes to the set of compaction rams and die-plates, which are known to be complementary. EP 0 620 108 A1 has made known to provide the shank of at least one compaction ram of a set of compaction rams with a recess in which a data carrier is received. The data carrier, for example, may be a so-called chip in which electronically predetermined information is stored, e.g. the label for the type of compaction tool, its previous service life, its residual tool life or also tolerances of the set. The label described may then be read by means of a reading device mounted at the location of the tabletting machine and may be automatically transferred to the process control computer. The process control computer will then take into account such information in selecting the operation program for the tabletting machine.
In the known prior art, it is impossible to identify an individual compaction ram or individual die-plate. In the operation of a tabletting machine, it frequently happens that individual die-plates and/or compaction rams need to be exchanged. The constant quality of the tablets may then be risked unless particular provisions are made.
What was stated for compaction rams also applies to die-plates. It is understood that each position of a die-plate or couple of rams is also identified in relation to its location in the rotor of the tabletting machine. This is commonly done by means of the process control computer. An identification is not made or is unnecessary with regard to the position of the compaction ram and/or die plate.